A stilbene derivative photoinitiator, a preparation method thereof, a photocuring film material and a preparation method and application thereof

Abstract

The application discloses a biphenyl derivative photoinitiator, a preparation method thereof, a photocuring film material and a preparation method and application thereof. The biphenyl derivative photoinitiator has a structural formula as shown in formula (I), R1 is an electron donor group, and R2 is an electron acceptor group. In the application, the biphenyl is used as a main body structure, different donor groups R1 and acceptor groups R2 are connected, a photoinitiator is synthesized through a Suzuki reaction, and a polymer monomer material is N,N-dimethyl acrylamide (DMA). The photocuring material with long afterglow luminescence can be obtained through a method of ultraviolet light irradiation, under the irradiation of a 365 nm ultraviolet lamp, the initiator absorbs photons to generate active species to attack double bonds in monomers to initiate a polymerization reaction. The photocuring film can produce long afterglow luminescence for several seconds after light irradiation, and can be applied to aspects of anti-counterfeiting, 3D printing and photolithography.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic light-emitting material, more particularly to a biphenyl derivative photoinitiator, a preparation method thereof, a photocured film material and a preparation method and application thereof. BACKGROUND

[0002] Free radical photopolymerization in photocuring technology is attracting much attention due to its green environmental protection and fast reaction speed; photoinitiators in free radical polymerization play a very important role, which affects the polymerization rate and the physical strength of the polymer after polymerization. Therefore, photoinitiators with excellent performance have always been a research hotspot. Among them, the photoinitiator requires non-toxicity, non-yellowing and low cost, which is the goal pursued by researchers.

[0003] Then, the synthesis of the photoinitiator material in the prior art is relatively complex, and the yield is not high; in addition, additional addition of iodonium salt, sulfonium salt and other initiators is required in the polymerization process, which will increase the cost. Therefore, it is necessary to further find photoinitiator materials with excellent performance.

[0004] SUMMARY

[0005] In order to overcome one of the problems existing in the prior art, the primary object of the present application is to provide a biphenyl derivative photoinitiator, which is synthesized by Suzuki reaction by connecting an acceptor group and a donor group to a biphenyl derivative.

[0006] Another object of the present application is to provide a preparation method of the biphenyl derivative photoinitiator.

[0007] Another object of the present application is to provide a photocured film material comprising the biphenyl derivative photoinitiator.

[0008] Another object of the present application is to provide an application of the biphenyl derivative photoinitiator.

[0009] The above objects of the present application are achieved by the following technical solutions:

[0010] A biphenyl derivative photoinitiator has the following molecular structure shown in formula (I):

[0011]

[0012]

[0013] wherein R1 is an electron donor group, and R1 is selected from any one of the following groups:

[0014]

[0015] wherein R2 is an electron acceptor group, R2 is selected from any one of the following groups:

[0016]

[0017] The diphenyl derivative in the present application is added into monomer DMA as a photoinitiator, and a long afterglow luminescent film material is obtained after photocuring. This kind of film material shows green long afterglow emission after irradiation by a 365 nm ultraviolet lamp. According to the long afterglow characteristics of the photocured film, it can be applied to the fields of anti-counterfeiting and information encryption.

[0018] The present application also provides a preparation method of the above-mentioned diphenyl derivative photoinitiator, comprising the following steps:

[0019] Under the protection of inert gas, 4-diphenylboronic acid, R-Br, tetrakis triphenylphosphine palladium, and a mixed solvent of aqueous potassium carbonate and tetrahydrofuran are reacted at 50-70°C for 5-10 hours to obtain the diphenyl derivative with the structure shown in formula (I).

[0020] The present application provides a photocured film material, comprising a photoinitiator and an olefin monomer, wherein the olefin monomer is N,N-dimethyl acrylamide, and the photoinitiator is the above-mentioned diphenyl derivative.

[0021] Preferably, the doping mass fraction of the photoinitiator material in the monomer material in the present application is 0.2%.

[0022] The present application also provides a preparation method of the above-mentioned photocured film material, comprising the following steps:

[0023] S1. The photoinitiator material is weighed into a clean and dry container, and the monomer is added until it is completely dissolved to prepare a formulation solution before photocuring;

[0024] S2. The formulation solution is uniformly coated on a glass slide at a doping mass fraction of the photoinitiator material in the monomer material of 0.2%, and then the formulation solution is cured by irradiation of a photocured film material ultraviolet lamp for 120 s to obtain a photocured film.

[0025] Preferably, the monomer in the step S1 is N,N-dimethyl acrylamide.

[0026] Preferably, in the step S2, the initiator is dissolved in the poly N,N-dimethyl acrylamide solution, and the initiator sample is completely dissolved by ultrasonic method.

[0027] More preferably, the wavelength of the ultraviolet lamp is 365 nm, and the power is 10 mW / cm 2 .

[0028] The application of the above light-cured film material in the field of anti-counterfeiting, 3D printing and photoetching.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] The application connects different electron donor groups R1 and electron acceptor R2 on biphenyl, synthesizes biphenyl derivatives through Suzuki reaction, forms D-A structure between the donor and acceptor of the biphenyl derivatives, effectively reduces the singlet-triplet energy level difference (ΔE ST ), thereby promoting the self-selected orbital coupling, thereby generating more triplet excitons. The biphenyl derivatives are synthesized through Suzuki reaction, the synthesis steps are simple, and the yield is high. The monomer material DMA is an easily obtained and inexpensive industrial production monomer, and the polymer after polymerization has good physical properties. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The HMNR diagram of the biphenyl derivative A1 prepared for Example 1 of the application. 1 HMNR diagram.

[0032] Figure 2 The HMNR diagram of the biphenyl derivative A2 prepared for Example 2 of the application. 1 HMNR diagram.

[0033] Figure 3 The polymerization degree diagram of the DMA monomer initiated by the biphenyl derivative A1 prepared for Example 1 of the application.

[0034] Figure 4 The polymerization degree diagram of the DMA monomer initiated by the biphenyl derivative A2 prepared for Example 2 of the application.

[0035] Figure 5 The polymerization mechanism diagram of the DMA monomer initiated by the photoinitiator biphenyl derivative A1 prepared for Example 1 of the application.

[0036] Figure 6 The application of the light-cured film in the anti-counterfeiting field.

[0037] Figure 7 The schematic diagram of the polymerization of the monomer initiated by the initiator. DETAILED DESCRIPTION

[0038] The embodiments of the application will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only for illustration of the application and should not be regarded as limiting the scope of the application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market.

[0039] It should be noted that:

[0040] In the present application, all the embodiments and preferred embodiments mentioned in the present application can be combined with each other to form new technical solutions, if not otherwise specified.

[0041] In the present application, percentage (%) or part refers to the percentage by weight or weight parts of the composition, if not otherwise specified.

[0042] In the present application, the components or preferred components involved can be combined with each other to form new technical solutions, if not otherwise specified.

[0043] In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand notation for any real number combination between a and b, where a and b are real numbers. For example, the numerical range "1~5" represents that all real numbers between "1~5" have been listed herein, and "1~5" is only a shorthand notation for these numerical combinations.

[0044] The "range" disclosed in the present application in the form of lower limit and upper limit can be one or more lower limits and one or more upper limits, respectively.

[0045] In the present application, unless otherwise specified, each reaction or operation step can be carried out sequentially or according to the sequence. Preferably, the reaction method herein is carried out sequentially.

[0046] Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied in the present application.

[0047] The present application provides a biphenyl derivative photoinitiator, which has a molecular structure as shown in the following formula (I):

[0048]

[0049] In the formula, R1 is an electron donor group, and R1 is selected from any one of the following groups:

[0050]

[0051] In the formula, R2 is an electron acceptor group, and R2 is selected from any one of the following groups:

[0052]

[0053] In the present application, different electron donor groups R1 and electron acceptor R2 are connected on biphenyl, and biphenyl derivatives are synthesized by Suzuki reaction. The donor-acceptor structure between the biphenyl derivatives can effectively reduce the singlet-triplet energy level difference (ΔEST ), thereby promoting self-tracked coupling, thereby generating more triplet excitons. The synthesis of the biphenyl derivative is simple and has a high yield, and the monomer material DMA is an easily available and inexpensive industrial production monomer, and the polymer after polymerization has good physical properties.

[0054] In some preferred embodiments, the biphenyl derivative photoinitiator of the present application can be selected from any one of the following structural formulae:

[0055]

[0056] In some preferred embodiments, the present application also provides a preparation method of the above-mentioned biphenyl derivative photoinitiator, comprising the following steps:

[0057] Under the protection of inert gas, 4-biphenyl boronic acid, R-Br, tetrakis triphenyl phosphine palladium, and a mixed solvent of aqueous potassium carbonate and tetrahydrofuran are reacted at 50-70°C for 5-10 hours to obtain a biphenyl derivative having the structure shown in formula (I).

[0058] The present application also provides a photocured film material comprising a photoinitiator and an olefin monomer, wherein the olefin monomer is N,N-dimethyl acrylamide, and the photoinitiator is the above-mentioned biphenyl derivative.

[0059] In some preferred embodiments, the doping mass fraction of the photoinitiator material in the monomer material in the photocured film material of the present application is 0.2%.

[0060] The present application also provides a preparation method of the above-mentioned photocured film material, comprising the following steps:

[0061] S1. Weigh the photoinitiator material into a clean and dry container, add the monomer to completely dissolve to prepare the formulation solution before photocuring;

[0062] S2. The formulation solution is uniformly coated on the glass slide with the photoinitiator material doped in the monomer material at a mass fraction of 0.2%, and then irradiated by a photocured film material ultraviolet lamp for 120s to solidify the formulation solution to obtain a photocured film.

[0063] In some preferred embodiments, the monomer in step S1 is N,N-dimethyl acrylamide.

[0064] In some preferred embodiments, in step S2, the initiator is dissolved in the poly N,N-dimethyl acrylamide solution, and the initiator sample is completely dissolved by ultrasonic method.

[0065] In some preferred embodiments, the wavelength of the UV lamp is 365 nm and the power is 10 mW / cm 2 .

[0066] The application also provides the application of the above-mentioned light-cured film material in the fields of anti-counterfeiting, 3D printing and photoetching.

[0067] The preparation method of the compound of the biphenyl derivative photoinitiator of formula (I) will be described in detail below.

[0068] Example 1

[0069] This embodiment provides a biphenyl derivative photoinitiator, the structural formula of which is shown as A1:

[0070]

[0071] The reaction equation and preparation method of the compound are as follows:

[0072]

[0073] Take 4-boronic acid triphenylamine (1.15 g, 4 mmol), bromobenzene (0.30 g, 2 mmol), tetrakis triphenylphosphine palladium (0.11 g, 0.1 mmol), and potassium carbonate (1.1 g, 8 mmol) into a 250 ml two-necked flask, vacuumize and fill with nitrogen, then add 20 ml of tetrahydrofuran solvent and 4 ml of water, stir and react under nitrogen protection at 70℃ for 8 hours. After the reaction is completed, cool it to room temperature, extract it with dichloromethane, and separate it by silica gel column chromatography (eluent: petroleum ether:dichloromethane = 6:1).

[0074] Example 2

[0075] This embodiment provides a biphenyl derivative, the structural formula of which is shown as A2:

[0076]

[0077] The reaction equation and preparation method of the compound are as follows:

[0078]

[0079] Into a 250 ml two-necked flask, 4-bromo triphenylamine (648 mg, 2 mmol), p-fluorobenzoic acid (601 mg, 4 mmol), tetrakis triphenylphosphine palladium (0.11 g, 0.1 mmol), potassium carbonate (1.1 g, 8 mmol) were weighed, and then the flask was vacuumed and filled with nitrogen. After that, 20 ml of tetrahydrofuran and 4 ml of water were added. The reaction was carried out under nitrogen protection at 70°C for 8 hours. After the reaction was completed, the product was cooled to room temperature, extracted with dichloromethane, and then separated by silica gel column chromatography (eluent: petroleum ether:dichloromethane = 5:1).

[0080] Performance test

[0081] The diphenyl derivative photoinitiators A1 and A2 obtained from Example 1 and Example 2 were characterized and tested for performance.

[0082] The test method is as follows:

[0083] Compound structure detection: Bruker 400 MHz superconducting nuclear magnetic resonance instrument was used, and deuterated chloroform or deuterated dichloromethane was used as the solvent;

[0084] Mass spectrometry detection: A1, A2, and A3 prepared in Example 1, Example 2, and Example 3 were dissolved in dichloromethane to prepare a solution with a concentration of 1 mg / mL. Liquid chromatography-mass spectrometry LCMS-2020 was used for mass spectrometry test.

[0085] Ultraviolet absorption spectrum detection: Shimadzu ultraviolet visible spectrophotometer UV-2700 was used, and the scanning range was 200-450 nm;

[0086] Emission spectrum detection: steady-state / transient fluorescence spectrometer (FLS980) was used, and the excitation wavelength was 310 nm,

[0087] The test temperature was 300 K under nitrogen protection.

[0088] The test results are as follows:

[0089] The product prepared in Example 1 was detected by nuclear magnetic resonance. Bruker 400 MHz superconducting nuclear magnetic resonance instrument was used, deuterated chloroform was used as the solvent, and the structure formula was determined. The hydrogen spectrum obtained by determination is shown in Figure 1 The characteristic wave number (ppm) is 1 H NMR (400 MHz, Chloroform-d) δ 7.55-7.35 (m, 6H), 7.27 (td, J = 7.3, 1.4 Hz, 4H), 7.17-7.08 (m, 6H), 7.07-7.01 (m, 2H). It can be seen that the molecular hydrogen spectrum peak can be one-to-one corresponding to the target product, and the number is reasonable. It is shown that the compound represented by diphenyl biologic A1 is prepared in Example 1, and the compound structure is single and high in purity;

[0090] The product prepared in Example 2 was subjected to nuclear magnetic resonance detection. Specifically, a Bruker 400MHz superconducting nuclear magnetic resonance instrument was used, and deuterated chloroform was used as the solvent for structure determination. The hydrogen spectrum obtained by measurement is shown in Figure 2 , and the characteristic wave number (ppm) is 1 H NMR (400 MHz, Chloroform-d) δ 7.53-7.48 (m, 1H), 7.43-7.39 (m, 1H), 7.29-7.24 (m, 2H), 7.14-7.00 (m, 5H). It can be seen that the molecular hydrogen spectrum peak can be one-to-one corresponding to the target product, and the number is reasonable. It is shown that the compound represented by biphenyl derivative A2 prepared in Example 2 is obtained, and the compound structure is single and high in purity.

[0091] Figure 3 The polymerization degree graph of the DMA monomer initiated by the biphenyl derivative A1 prepared in Example 1 of the present application is shown in Figure 3 It can be seen that under the condition of LED @ 365 nm, the power is 10 mW / cm 2 , and with the gradual increase of the content of the photoinitiator A1, the conversion rate monitored by 1 HNMR within 120 s shows an increase first and then tends to be balanced, and with the increase of the irradiation time of the ultraviolet light LED, the viscosity of the sample gradually increases. Finally, the content of the photoinitiator is selected as 0.2wt%, and the conversion rate can reach 71%.

[0092] Figure 4 The polymerization degree graph of the DMA monomer initiated by the biphenyl derivative A2 prepared in Example 2 of the present application is shown in Figure 4 It can be seen that under the condition of LED @ 365 nm, the power is 10 mW / cm 2 , and with the gradual increase of the content of the photoinitiator A2, the conversion rate monitored by 1 HNMR within 120 s shows an increase first and then tends to be balanced, and with the increase of the irradiation time of the ultraviolet light LED, the viscosity of the sample gradually increases. Finally, the content of the photoinitiator is selected as 0.2wt%, and the conversion rate can reach 95%.

[0093] Table 1: The conversion rate of DMA in A1 / Iod or A2 / Iod system under LED @ 365 nm irradiation

[0094]

[0095] Figure 5 The polymerization mechanism graph of the DMA monomer initiated by the photoinitiator biphenyl derivative A1 prepared in Example 1 of the present application is shown in Figure 5As can be seen, the photoinitiator generates active species after being excited by light, which attacks the olefin double bond in the monomer to initiate chain polymerization and finally generates PDMA polymer.

[0096] Figure 6 For the application of the photocured film in the anti-counterfeiting field. From Figure 6 As can be seen, the PDMA photocured film generated after the monomer is polymerized has the characteristic of long afterglow emission. The film generates a school badge pattern under laser etching and has afterglow emission after light irradiation.

[0097] Figure 7 For the schematic diagram of the initiator initiating the polymerization of the monomer. From Figure 7 As can be seen from the above, the initiator molecules are dispersed in the monomer without light irradiation. After the system is irradiated by a UV lamp, active species are generated due to the energy absorption of the initiator, so that the monomer undergoes chain polymerization and finally generates a polymer.

[0098] The application provides a biphenyl derivative photoinitiator, which has a molecular structure shown in the following formula (I):

[0099]

[0100] In the formula, R1 is an electron donor group, and R1 is selected from any one of the following groups:

[0101]

[0102] In the formula, R2 is an electron acceptor group, and R2 is selected from any one of the following groups:

[0103]

[0104] The application also provides a photocured film material, which comprises a photoinitiator and an olefin monomer, wherein the olefin monomer is N,N-dimethyl acrylamide, and the photoinitiator is the above biphenyl derivative.

[0105] In summary, the application connects different electron donor groups R1 and electron acceptors R2 on biphenyl, synthesizes a biphenyl derivative through Suzuki reaction, forms a D-A structure between the donor and acceptor of the biphenyl derivative, effectively reduces the singlet-triplet energy level difference (ΔE ST ), thereby promoting the self-selected orbital coupling and generating more triplet excitons. The biphenyl derivative is synthesized through Suzuki reaction, the synthesis steps are simple, the yield is high, the monomer material DMA is an easily obtained and cheap industrial production monomer, and the polymer generated after the polymerization has good physical properties.

[0106] The biphenyl derivative in the present application has a structural formula as shown in formula (I), R1 is an electron donor group, and R2 is an electron acceptor group. The present application takes biphenyl as the main body structure, connects different donor groups R1 and acceptor groups R2, and synthesizes a photoinitiator through Suzuki reaction, and the polymer monomer material is N,N-dimethyl acrylamide (DMA). The photopolymerizable material with long afterglow luminescence can be obtained by the method of ultraviolet light irradiation. Under the irradiation of a 365 nm ultraviolet lamp, the initiator absorbs photons to generate active species to attack the double bond in the monomer to initiate the polymerization reaction. The photopolymerization film can produce long afterglow luminescence for several seconds after light irradiation, and can be applied to anti-counterfeiting, 3D printing, photolithography and the like.

[0107] Meanwhile, the present application realizes controllable preparation of the biphenyl derivative photoinitiator, has low preparation cost, wide raw material sources, can realize large-scale production, and has broad commercialization prospects.

[0108] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0109] Although several embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method of making a photocured thin film material, characterized by, The light-cured film material formula comprises a photo initiator and an olefin monomer, wherein the olefin monomer is N,N-dimethyl acrylamide, the photo initiator is a biphenyl derivative photo initiator and is selected from one of the following structural formula A1 or A2: the method of making comprising the steps of: S1. The photo initiator material is weighed into a clean and dry container, and the monomer is added to completely dissolve to configure a formula solution before light curing; S2. The formula solution is uniformly coated on a glass slide at a doping mass fraction of 0.2% of the photo initiator material in the monomer material, and then the formula solution is cured by light-cured film material ultraviolet lamp irradiation for 120s to obtain a light-cured film.

2. The method for preparing the photocurable thin film material according to claim 1, characterized in that, In the step S2, the initiator is dissolved in the N,N-dimethyl acrylamide solution, and the ultrasonic method is used to completely dissolve the initiator sample.

3. The method for preparing the photocurable thin film material according to claim 1, characterized in that, The wavelength of the UV lamp is 365 nm, and the power is 10 mW / cm 2 .

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